Advanced composite materials technology for rotorcraft

Composite materials are increasingly used in rotorcraft structures to reduce weight and improve efficiency. The rotorcraft industry is constantly in need of higher-performance materials that offer improved mechanical strength and stiffness at a lower weight. In polymer-matrix composite structures, matrix-dominated failures impose severe limitations on structural performance. The objective of this work is to advance composite material technologies for rotorcraft through the use of nanoadditives to improve structural efficiency. Technical challenges and potential solutions for improving matrix-dominated performance of prepreg composites through nanoparticle reinforcement, are discussed. In particular, a promising technology for improving compression and interlaminar strength and fatigue performance, is identified. The advanced materials technology is based on high weight content loading of approximately 100-nm diameter nanosilica particles in low-viscosity resins. Such technology resulted in compression strength improvement for intermediate-modulus carbon-fiber/epoxy-matrix 250° F curing prepreg composites as recently demonstrated by 3M. This work not only supports the initial findings of 3M regarding the improvement of compression strength performance but also demonstrates improved interlaminar material properties including fatigue performance, and expands the material design space. Fatigue performance is critical to rotorcraft dynamic components as they are subject to extreme oscillatory flight loads that can result in material fatigue failures.